Cooling unit

ABSTRACT

A cooling unit includes a motor, a driving shaft, a first fan, a second fan, and a fan shroud. The driving shaft extends from the motor and is disposed parallel to a core of a heat exchanger. The first fan is disposed to oppose the core for generating air for cooling the core. The first fan has a first rotation shaft connected to the driving shaft through a gear such that the first fan is rotated by the driving shaft. The fan shroud is configured to support the first fan and conduct the air from the core to the first fan. The second fan has a second rotation shaft disposed coaxial with the driving shaft and rotatable with the driving shaft. The second fan is rotated by the driving shaft when the first fan is rotated, thereby to supply the motor with air for cooling the motor.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2007-335909filed on Dec. 27, 2007, the disclosure of which is incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to a cooling unit having a fan driven by amotor through a gear mechanism, which is, for example, used forgenerating air for cooling a heat exchanger, such as a radiator of avehicle.

BACKGROUND OF THE INVENTION

A cooling unit having fans driven by a single motor through agear-driving mechanism is, for example, described in Japanese UnexaminedPatent Application Publication No. 2006-145177. In the described coolingunit, the fans are arranged in parallel with each other behind a core ofa heat exchanger. The fans generate air for cooling the core whenrotated. The motor has a driving shaft extending parallel to the core.The driving shaft is connected to rotation shafts of the fans throughgears, so that the fans are rotated by rotation of the driving shaft.

The described cooling unit further has a fan shroud disposed adjacent tothe motor and surrounding outer peripheries of the fans. The fan shroudis formed with through holes, and the driving shaft passes through thethrough holes. When the fans are rotated by the driving shaft throughthe gears, air around the motor is conducted to negative pressure sidesof the fans through the through holes of the fan shroud while flowingaround the motor, and hence the motor is cooled.

SUMMARY OF THE INVENTION

In such a cooling unit, the motor is cooled by air caused by negativepressure of the fans. However, when the amount of air generated by thefans is small, it is difficult to rely on the effect of the negativepressure. That is, because the fans are originally provided for coolingthe core, it is difficult to normally and stably supply the motor withair for cooling the motor. If the amount of air for supplied to themotor is increased, it will be difficult to maintain the capacity ofcooling the core.

The present invention is made in view of the foregoing matter, and it isan object of the present invention to provide a cooling unit having afan driven by a motor through a gear, which is capable of stablyproviding the motor with cooling air.

According to an aspect of the present invention, a cooling unit includesa motor, a driving shaft, a first fan, a second fan, and a fan shroud.The driving shaft extends from the motor and is disposed parallel to acore of a heat exchanger. The first fan is opposed to the core forgenerating the air for cooling the core. The first fan has a firstrotation shaft connected to the driving shaft through a gear to berotated by the driving shaft. The fan shroud supports the first fan andis configured to conduct the air from the core toward the first fan. Thesecond fan has a second rotation shaft and is configured to generate airfor cooling the motor. The second rotation shaft is disposed coaxialwith the driving shaft and rotatable with the driving shaft such thatthe second fan is rotated by the driving shaft when the first fan isrotated.

In such a construction, the second fan is coaxially coupled to thedriving shaft for driving the first fan. Therefore, since the second fanis rotated by the driving shaft together with the first fan, apredetermined volume of air can be supplied to the body by the secondfan, irrespective of the volume of air supplied to the heat exchanger.The capacity of cooling the motor improves.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention willbecome more apparent from the following detailed description made withreference to the accompanying drawings, in which like parts aredesignated by like reference numbers and in which:

FIG. 1 is a schematic cross-sectional view of a cooling unit, whenviewed from a top, according to a first embodiment of the presentinvention;

FIG. 2 is a schematic cross-sectional view of a cooling unit accordingto a first example of a second embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a cooling unit accordingto a second example of the second embodiment;

FIG. 4 is a schematic cross-sectional view of a cooling unit accordingto a third example of the second embodiment;

FIG. 5 is an end view of a motor of a cooling unit, when viewed along alongitudinal axis of a driving shaft, according to the secondembodiment;

FIG. 6 is a schematic cross-sectional view of a cooling unit accordingto a third embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a cooling unit accordingto a fourth embodiment of the present invention;

FIG. 8 is a schematic side view of a motor of the cooling unit, whenviewed along a longitudinal axis of a driving shaft, according to thefourth embodiment;

FIG. 9 is a back view of the motor according to the fourth embodiment;

FIG. 10 is a schematic cross-sectional view of a cooling unit accordingto a fifth embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view of a joint integrated into aboss part of a motor-cooling fan of a cooling unit according to a sixthembodiment of the present invention;

FIG. 12 is a plan view of an external gear of the joint according to thesixth embodiment;

FIG. 13 is a side view of the external gear, partly including across-section, when viewed along an arrow XIII in FIG. 12;

FIG. 14 is a plan view of an internal gear of the joint according to thesixth embodiment; and

FIG. 15 is a side view of the internal gear, partly including across-section, when viewed along an arrow XV in FIG. 14.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will now be describedwith reference to the accompanying drawings. Like parts are designatedby like reference numbers, and a description thereof is not repeated. Inthe drawings, an arrow X denotes one direction parallel to a core 2 of aheat exchanger 1. The direction X corresponds to a width direction of acooling unit, which corresponds to a left and right direction of avehicle. An arrow Y denotes a direction parallel to axes of fans forcooling the core 2. The direction Y is a frontward direction of thecooling unit, which corresponds to a frontward direction of the vehicle.

First Embodiment

The cooling unit of the present embodiment generally includes first fans10, a fan shroud 30, a motor device, and a second fan 20. The fans 10are located to a rear side of the core 2 of the heat exchanger 1 of avehicle, such as the radiator 1, and mainly generate air passing throughthe core 2, thereby to cool the core 2. Thus, the fans 10 arehereinafter also referred to as the core-cooling fans 10. The fan shroud30 is located to the rear side of the core 2 and supports thecore-cooling fans 10. The fan shroud 30 has air passage portions havinga generally tubular shape for conducting the air passing through thecore 2 to the core-cooling fans 10 in a direction opposite to thedirection Y.

The core-cooling fans 10 have rotation shafts 13 driven by the motordevice. The motor device has a motor 19 for generating a driving forceand a driving shaft 17 connected to the rotation shafts 13 of thecore-cooling fans 10 through gears 14, 15, 16 for transmitting thedriving force to the core-cooling fans 10. The second fan 20 has arotation shaft 18 that is coaxial with the driving shaft 17 of the motordevice. The driving shaft 18 is rotated in accordance with the rotationof the driving shaft 17 so that the second fan 20 generates air forcooling the motor 19. Hereinafter, the second fan 20 is also referred toas the motor-cooling fan 20.

The radiator 1 serves to cool an internal fluid, such as an enginecoolant. The radiator 1 generally includes the core 2, first and secondtanks 3 and reinforcement members for reinforcing the core 2. The core 2includes tubes through which the engine coolant flows and fins disposedbetween the tubes. The first and second tanks 3 are connected toopposite ends of the tubes. The first tank 3 serves to distribute theengine coolant into the tubes and the second tank 3 serves to collectthe engine coolant from the tubes.

Further, an inlet pipe that is in communication with a radiator circuitthrough which the engine coolant circulates is coupled to the first tank3 for introducing the engine coolant into the first tank 3. An outletpipe that is in communication with the radiator circuit is coupled tothe second tank 3 for introducing the engine coolant, which has passedthrough the radiator 1, from the second tank 3 into the radiatorcircuit. The inlet pipe and the outlet pipe extend from a rear side ofthe first tank 3 toward the engine.

The fan shroud 30 has a generally panel-like member and fixed to theradiator 1. The fan shroud 30 is configured to support and surround thecore-cooling fans 10. In the present embodiment, two core-cooling fans10 are disposed in parallel with each other with respect to the flow ofair passing through the core 2. That is, the two core-cooling fans 10are aligned in the direction X. The two core-cooling fans 10 are drivenby the single motor device through a gear mechanism including the gears14, 15, 16, which will be described later.

Each of the core-cooling fans 10 is an axial fan. The core-cooling fan10 generally has a boss part 12 fixed to the rotation shaft 13 andblades 11 radially extending from the boss part 12.

The fan shroud 30 has ring portions each having a ring shape. Thecore-cooling fans 10 are correspondingly disposed in the ring portionsof the fan shroud 30. In other words, the ring portions each surround anouter periphery of the blades 11 of the core-cooling fan 10. The airpassage portions of the fan shroud 30 extend from an outer edge of thecore 2 to the ring portions. The air passage portions define airpassages from the rear side of the core 2 to the ring portions. The airpassage portions are configured to efficiently conduct air, such asoutside air, passing through the core 2 to the ring portions.

Each of the core-cooling fans 10 is disposed downstream of the radiator1 with respect to the flow of air passing through the core 2. Therotation shaft 13 extends in a direction parallel to the direction Y,such as in a vehicle front and rear direction. The core-cooling fan 10is rotated as the rotation shaft 13 is rotated by the driving shaft 17,thereby to draw air from an outside of an engine compartment of thevehicle through a front grill part of the vehicle in the vehiclerearward direction toward the engine.

The motor 19 is an electric motor, such as a ferrite d.c. motor. Themotor 19 rotates the core-cooling fans 10 through the gear mechanism.The motor 19 is provided with a harness, which is electrically coupledto a battery of the vehicle through a connector or the like. Thus,electric power is supplied to an armature of the motor 19 through theharness.

The motor 19 is disposed at an end of the driving shaft 17 and isprojected outside of the radiator 1 with respect to the right and leftdirection. That is, the motor 19 is offset from a side of the radiator 1by a predetermined distance in a direction opposite to the direction X.In such a configuration, a thickness of the cooling unit with respect tothe front and rear direction, such as the direction Y can be reduced.

The motor 9 is housed in a motor case 31. The motor case 31 has an airinlet opening 32 and an air outlet opening 33. The air inlet opening 32is located to a side of the tank 3 of the radiator 1 and is open in thefrontward direction Y. The air outlet opening 33 is open in thedirection X, such as in a longitudinal direction of the driving shaft17. For example, the motor case 31 can be configured such that adownstream end of the motor case 31 with respect to a flow of air in themotor case 31 constitutes a part of the air passage portion of the fanshroud 30.

The motor case 31 can be made of a resin, such as polypropylene,containing glass fiber, talc and the like so as to have sufficientstrength. The motor case 31 can be integrally formed with the fan shroud30. For example, the motor case 31 can be integrally molded with the fanshroud 30 such as by injection molding using a predetermined mold.

Alternatively, the motor case 31 can be provided as an individualmember. In such a case, the motor case 31 and the fan shroud 30 areseparately formed, and then the motor case 31 is fixed to the fan shroud30, another member mounted in the vehicle, or a part of a vehicle body.

The driving shaft 17 extends from the motor 19 in the direction X. Thedriving shaft 17 is parallel to the core 2 and located to rear sides ofthe blades 11 of the core-cooling fans 10. The rotation shafts 13 of thecore-cooling fans 10 are provided with driven gears 14. A first drivinggear 15 is fixed to the driving shaft 17, and engages with the drivengear 14 of the rotation shaft 13 of the core-cooling fan 10, which islocated closer to the motor 19 than the other fan 10, such as, a leftfan 10 in FIG. 1. A second driving gear 16 is fixed to an end of thedriving shaft 17 opposite to the motor 19, and engages with the drivengear 14 of the rotation shaft 13 of the core-cooling fan 10, which islocated further from the motor 19 than the other fan 10, such as, aright fan 10 in FIG. 1.

The first driving gear 15 is rotated with the driving shaft 17, and thedriven gear 14 is engaged with the first driving gear 15. Thus, thedriving force generated by the motor 19 is transmitted to thecore-cooling fan 10, which is located closer to the motor 19, throughthe driving shaft 17, the first driving gear 15, the driven gear 14, andthe rotation shaft 13. Likewise, the second driving gear 16 is rotatedwith the driving shaft 17, and the driven gear 14 is engaged with thesecond driving gear 16. Thus, the driving force generated by the motor19 is also transmitted to the core-cooling fan 10, which is locatedfurther from the motor 19, through the driving shaft 17, the seconddriving gear 16, the driven gear 14 and the rotation shaft 13. That is,the two core-cooling fans 10 are rotated by the rotation of the drivingshaft 17 through the gears 14, 15, 16.

For example, the first and second driving gears 15, 16 and the drivengears 14 are constructed of a bevel gear, a helical gear, and the like.A gear ratio of the driving gear 15, 16 to the driven gear 14 can bearbitrarily set in a predetermined range. The gear ratio of the firstdriving gear 15 to the corresponding driven gear 14 and the gear ratioof the second driving gear 16 to the corresponding driven gear 14 can bedifferentiated such that the volumes of air blown the two core-coolingfans 10 are different. Also, the volume of air for cooling the motor 19and the volume of air for cooling the radiator 1 can be adjusted to havea suitable relationship by adjusting the gear ratios.

The motor-cooling fan 20 has blades 21 and a boss part 22 including therotation shaft 18 and supporting the blades 21. The blades 21 radiallyextend from the boss part 22. The boss part 22 is formed with therotation shaft 18. The motor-cooling fan 20 is disposed such that therotation shaft 18 is coaxial with the driving shaft 17. In the presentembodiment, the motor-cooling fan 20 is an axial fan. For example, themotor-cooling fan 20 can be a propeller fan.

The rotation shaft 18 of the motor-cooling fan 20 rotates with therotation of the driving shaft 17. When rotated, the motor-cooling fan 20causes air to flow from an upstream location of the blades 21 facing themotor 19 in the direction X. As such, the outside air is suctioned intothe motor case 31 from the air inlet opening 32, which is open to a sideof the tank 3. The suctioned air flows around the motor 19 inside of themotor case 31 and then flows out from the motor case 31 through the airoutlet 33 in the direction X. As such, the motor 19 is cooled.

That is, as the driving shaft 17 rotates, the motor-cooling fan 20 andthe core-cooling fans 10 are respectively rotated at predetermined gearratios. Thus, cooling operation of the radiator 1 and the motor 19 aresimultaneously performed.

Recently, the number of electric components mounted in an enginecompartment of the vehicle has been increased in accordance withimprovement of performance of the vehicle. On the other hand, it hasbeen required to reduce the size of vehicle. As such, allowable spacesfor mounting the components in the engine compartment tend to bereduced. With this, it is required to reduce the size of the coolingunit as small as possible. In the present embodiment, the dimension ofthe cooling unit in the front and rear direction can be reduced by theabove-described arrangement while improving the capacity of cooling theheat exchanger 1 and the motor 19.

In the present embodiment, the cooling unit includes the twocore-cooling fans 10 for cooling the core 2 of the radiator 1, the fanshroud 30, the motor 19, the driving shaft 17 and the motor-cooling fan20 for cooling the motor 19. The two core-cooling fans 10 are arrangedin parallel with each other behind the core 2, and generate the airpassing through the core 2 for cooling the core 2. The fan shroud 30 isarranged behind the core 2 and configured to conduct the air passingthrough the core 2 toward the downstream positions of the core-coolingfans 10. The driving shaft 17 is disposed behind the core 2 and extendsparallel to the core 2. The driving shaft 17 is connected to therotation shafts 13 of the core-cooling fan 10 through the gears 14, 15,16. The motor-cooling fan 20 is arranged such that the rotation shaft 18thereof is coaxial with the driving shaft 17. The rotation shafts 13, 18are rotated by the rotation of the driving shaft 17.

Accordingly, the motor-cooling fan 20 can be driven together with thecore-cooling fans 10. The predetermined volume of air is supplied to themotor 19 irrespective of the volume of the air supplied to the radiator1. Therefore, the cooling unit ensures the predetermined coolingcapacity for cooling the motor 19.

Second Embodiment

A second embodiment will now be described with reference to FIGS. 2 to5. In the present embodiment, the motor 19 is arranged to a rear side ofthe radiator 1. FIGS. 2 to 4 show first, second third examples of thepresent embodiment, respectively. FIG. 5 shows the motor device whenviewed along the longitudinal direction of the driving shaft 17, such asin the direction X.

In the first example of the present embodiment shown in FIG. 2, thelocation of the motor 19 is different from that of the first embodimentshown in FIG. 1. Specifically, the motor 19 is located behind the tank 3of the radiator 1. Also, the motor 19 is located to a side of a vehiclebody member 4, such as a member supporting the radiator 1 with respectto the direction X. That is, the motor 19 is overlapped with theradiator 1 with respect to the left and right direction. Otherstructures are similar to the first embodiments, and thus the similareffects are achieved by those similar structures.

In the first example of the second embodiment, the cooling unit has amotor case 31A and a motor-cooling fan 20A, in place of the motor case31 and the motor-cooling fan 20 of the first embodiment.

The motor 19 is housed in the motor case 31A. The motor case 31A has anair inlet opening 32A and an air outlet opening 33A. The air inletopening 32A is provided on a plane perpendicular to a longitudinal axisof the driving shaft 17, and is open in the direction opposite to thedirection X. The air inlet opening 32A is widely open in the directionopposite to the direction X such that an axial end of the motor 19 isnot covered. For example, the air inlet opening 32A is formed on anentirety of an axial end of the motor case 31A, and has across-sectional area that is substantially equal to a cross-sectionalarea of a main part of the motor case 31A surrounding the motor 19. Theair outlet opening 33A is located to the rear side of the tank 3 and inan air-blowing region of the core-cooling fan 10. That is, the airoutlet opening 33A is open to a downstream location of the fan 10 behindthe tank 3. Further, the air outlet opening 33A is open in the directionX.

The motor case 31A can be configured such that the downstream endthereof constitutes a part of the air passage portion of the fan shroud30. The motor case 31A can be integrally formed with the fan shroud 30.In such a case, the motor case 31A can be made of a resin, such aspolypropylene, containing glass fiber, talc and the like so as to havesufficient strength. Alternatively, the motor case 31A can be anindividual member. In such a case, the motor case 31A and the fan shroud30 are separately formed, and then the motor case 31A can be fixed tothe fan shroud 30, another member mounted in the vehicle, or a part ofthe vehicle body.

The motor-cooling fan 20A has a rotation shaft 18 disposed to be coaxialwith the driving shaft 17, similar to the rotation shaft 18 of the firstembodiment. In the first example of the present embodiment, the motor 19is located immediately behind the tank 3 of the radiator 1, and themotor-cooling fan 20A is offset from the tank 3, such as in thedirection X. Therefore, a diameter of the motor-cooling fan 20Aincluding blades 21A and a boss part 22A can be increased greater than adiameter of the motor-cooling fan 20 of the first embodiment. Forexample, the diameter of the motor-cooling fan 20A can be increased tobe equal to a dimension of the motor 19 in the front and rear direction.As such, the volume of air generated by the motor-cooling fan 20A isincreased, and thus cooling capacity for cooling the motor 19 improves.Other structures of the first example of the second embodiment aresimilar to the first embodiment, and thus the similar effects areachieved.

In the second example of the present embodiment shown in FIG. 3, themotor 19 is arranged behind the tank 3 of the radiator 1, similar to thefirst example shown in FIG. 2. The motor 19 and the motor-cooling fan20A are housed in a motor case 31B, in place of the motor case 31A. Themotor case 31B has an air inlet opening 32B at a similar location as theair inlet opening 32A of the motor case 31A. However, the motor case 31Bhas an air outlet opening 33B at a location different from the airoutlet opening 33A of the motor case 31A. Other structures of the secondexample shown in FIG. 3 are similar to the first embodiment, and thusthe similar effects are achieved by those similar structures.

Specifically, the air outlet opening 33B is located more to a frontposition than the blades 11 of the core-cooling fan 10 with respect tothe front and rear direction. The air outlet opening 33B is located in anegative pressure region, that is, in an air suctioning region of thecore-cooling fan 10.

In such a construction, a suction force generated by the core-coolingfan 10 is also exerted to the air inside of the motor case 31B.Accordingly, the air blown by the motor-cooling fan 20A can be drawn tothe negative pressure region of the core-cooling fan 10 and furtherconducted to the downstream location of the core-cooling fans 10, withthe air passing through the core 2 of the radiator 1 in the rearwarddirection, by means of the core-cooling fan 10. Because the volume ofair flowing around the motor 19 can be further increased by the suctionforce of the core-cooling fan 10, the cooling capacity for cooling themotor 19 is further improved.

The motor case 31B is configured such that a downstream portion thereofdownstream of the motor 19 constitutes a part of the air passage portionof the fan shroud 30. In such a case, the air outlet opening 33B isdisposed to open to the inside of the fan shroud 30, particularly, toopen to the air passage portion of the fan shroud 30.

The air inlet opening 32B is widely open on a side of the motor case 31Bsuch that the entirety of the axial end of the motor 19 facing thedirection opposite to the direction X is not covered. The air outletopening 33B is located at the downstream portion of the motor case 31Bconstituting the part of the air passage portion of the fan shroud 30 toallow communication between the inside of the motor case 31B and thenegative pressure region of the fan shroud 30.

According to the above configurations of the air inlet opening 32B andthe air outlet opening 33B, as the motor-cooling fan 20A is rotated byrotation of the driving shaft 17, the air is suctioned to the inside ofthe motor case 31B from the air inlet opening 32B. The air flows aroundthe entire circumference of the motor 19 and toward a downstreamlocation of the motor-cooling fan 20A. Further, the air flows in thefrontward direction toward the air outlet opening 33B and then flows outfrom the air outlet opening 33B to the negative pressure region of thecore-cooling fan 10.

Particularly, since the air inlet opening 32B is widely open, the airflows to surround the motor 19 inside of the motor case 31B. Inside ofthe motor case 31B, a part of the air flows along a rear surface of themotor 19. The part of the air further moves to a front side of the motor19 and flows along a front surface of the motor 19 while flowing towardthe air outlet opening 33B. Therefore, the distance of the airflow pathwithin the motor case 31B is increased. An entire outer surface of themotor 19 is efficiently cooled.

The motor case 31B can be integrally formed with the fan shroud 30,similar to the motor case 31 of the first embodiment. In such a case,the motor case 31B is formed of a resin, such as polypropylene,containing glass fiber, talc, and the like so as to have sufficientstrength. Alternatively, the motor case 31B and the fan shroud 30 can beseparately formed. In such a case, the motor case 31B is fixed to thefan shroud 30, another member mounted in the vehicle, or a part of thevehicle body.

In the third example of the second embodiment shown in FIG. 4, the motorcase 31B is modified to a motor case 31C. The motor case 31C has two airoutlet openings, such as a first air outlet opening 33C and a second airoutlet opening 34C. Other structures are similar to the second exampleshown in FIG. 3, and thus the similar effects are achieved by thosesimilar structures.

The first air outlet opening 33C is similar to the air outlet opening33B of the second example shown in FIG. 3. The first air outlet opening33C is located more to a front position than the blades 11 of thecore-cooling fan 10. The first air outlet opening 33C is open to thenegative pressure region of the core-cooling fan 10.

The second air outlet opening 34C is located at the downstream portionof the motor case 31C and more to a rear position than the driving shaft17. Also in the third example, the motor case 31C is configured toconstitute a part of the air passage portion of the fan shroud 30. Inother words, the first air outlet opening 33C is open to the inside ofthe fan shroud 30, particularly, open to the air passage portion of thefan shroud 30.

The motor case 31C has an air inlet opening 32C, similar to the airinlet opening 32A of the first example shown in FIG. 2. In the thirdexample, the first and second air outlet openings 33C, 34C can beconnected to each other. That is, the first and second air outletopenings 33C, 34C can be provided by a single opening. For example, thefirst and second air outlet openings 33C, 34C can be provided by atleast one opening provided on a side wall of the motor case 31C, theside wall facing in the direction X.

Accordingly, the air suctioned inside of the motor case 31C from the airinlet opening 32C is divided into a first path P1 and a second path P2,the first path P1 passing along a front outer surface of the motor 19and communicating with the negative pressure region of the core-coolingfan 10 through the first air outlet opening 33C, and the second path P2passing along a rear outer surface of the motor 19 and communicatingwith the downstream region of the core-cooling fan 10 through the secondair outlet opening 34C.

Therefore, when the volume of air generated by the core-cooling fan 10is large, the volume of air passing through the first path P1 can beeffectively increased by means of the suction force of the core-coolingfan 10. When the volume of air generated by the core-cooling fan 10 issmall or an area of the first air outlet opening 33C is small due to thespace of the first air outlet opening 33C being limited in accordancewith the requirement of the vehicle size reduction, the volume of aircooling the motor 19 can be ensured by the suction force of themotor-cooling fan 20A without largely relying on the suction force ofthe core-cooling fan 10. In the third example, therefore, the coolingcapacity for cooling the motor 19 is stably ensured.

The motor case 31C can be integrally formed with the fan shroud 30,similar to the motor case 31. For example, the motor case 31C can beformed of a resin material, such as polypropylene, containing glassfiber talc and the like so as to have sufficient strength.Alternatively, the motor case 31C and the fan shroud 30 can beseparately formed. In such a case, the motor case 31C can be fixed tothe fan shroud 30, another member mounted in the vehicle, or a part ofthe vehicle body.

In the present embodiment, a dimension of the cooling unit with respectto the right and left direction is reduced by the above configuration.Therefore, the dimension of the core 2 in the right and left directioncan be increased as much as possible within an allowed space.Accordingly, in addition to the improvement of the motor coolingcapacity, the cooling capacity of the radiator 1 can be improved. Thecooling unit of the present embodiment will be effectively used in acase where the space for the cooling unit is limited in the right andleft direction, but relatively allowed in the front and rear direction.

Further, as shown in FIG. 5, the air suctioned inside of the motor case31A, 31B, 31C from the air suction opening 32A, 32B, 32C flows throughthe entire circumference of the motor 19. Therefore, the cooling effectfor cooling the motor 19 further improves.

Third Embodiment

A third embodiment of the present invention will now be described withreference to FIG. 6. In the present embodiment, the cooling unit has acentrifugal motor-cooling fan 20B, in place of the axial fan.

Structures other than the motor-cooling fan 20B are similar to thestructures of the second example of the second embodiment shown in FIG.3, and thus the similar effects are achieved by those similarstructures.

The motor-cooling fan 20B is a centrifugal fan having a boss part 22Band blades 21B. The boss part 22B is formed with the rotation shaft 18,and the rotation shaft 18 is disposed to be coaxial with the drivingshaft 17. The blades 21B are arranged around the boss part 22B across apredetermined distance in the radial direction. The motor-cooling fan20B has a generally disc-like shape with a predetermined diameter and apredetermined axial dimension. The motor-cooling fan 20B is, forexample, a sirocco fan or a turbo fan.

In general, pressure loss is likely to increase in a case where a pathof cooling air for cooling the motor 19 is complex, a passage area ofthe path of the cooling air is small, and/or a space downstream of thefan is small. Even in such a case, the volume of air for cooling themotor 19 is ensured by employing the centrifugal fan.

The rotation shaft 18 of the motor-cooling fan 20B is rotated with therotation of the driving shaft 17. The air outside of the cooling unit issuctioned in the motor case 31B from the air inlet opening 32B with therotation of the motor-cooling fan 20B. Inside of the motor case 31B, theair is suctioned to a radially inner space of the motor-cooling fan 20Bin the direction X from an air suction port thereof, which is providedat a middle of an axial end of the centrifugal fan 20B and faces themotor 19. The air is then blown out in a centrifugal direction, such asin a radial direction, through the blades 21B. The air is furtherintroduced to the negative pressure region of the core-cooling fan 10through the air outlet opening 33B.

Accordingly, the air inside of the motor case 31B receives the suctionforce of the core-cooling fan 10, in addition to the suction force ofthe motor-cooling fan 20B. As such, the air flowing out of the motorcase 31B is introduced to the downstream position of the core-coolingfans 10 with the air passing through the core 2 in the rearwarddirection. Therefore, even if the pressure loss in the air path forcooling the motor 19 is large, the volume of air for cooling the motor19 is ensured. Further, the volume of air for cooling the motor 19 isincreased by means of the suction force generated by the core-coolingfan 10. As such, the capacity of cooling the motor 19 further improves.

In the present embodiment, even in a case where the space for mountingthe cooling unit in the engine compartment is limited in the right andleft direction, it is less likely that heated air passing through thecore 2 will flow into the motor case 31B since the centrifugal fan 20Bcan resist to high pressure loss.

Fourth Embodiment

A fourth embodiment of the present invention will now be described withreference to FIGS. 7 to 9. In the present embodiment, the cooling unitis configured such that air generated by the motor-cooling fan 20Apasses through a control device 40 and the motor 19 for cooling thecontrol device 40. FIG. 8 shows an internal structure of a motor case31D for explaining airflow therein, when viewed in the direction X. FIG.9 shows a back view of the motor case 31D, when viewed in the directionY. In FIGS. 8 and 9, the direction Z corresponds to an upward directionof the cooling unit, such as a direction perpendicular to a papersurface of FIG. 7.

As shown in FIGS. 7 to 9, the motor 19 and the control device 40 arehoused in the motor case 31D. Inside of the motor case 31D, a separationwall 35 is provided between the motor 19 and the control device 40. Thecontrol device 40 serves to control an operation of the motor 19. Thecontrol device 40 includes a control circuit board, electric componentsand heat radiation fins 41. The heat radiation fins 41 are exposed tothe air passage inside of the motor case 31D for radiating heat. Theseparation wall 35 is disposed above the motor 19 and under the controldevice 40.

The motor case 31D is configured such as a first side wall thereoffacing the core-cooling fan 10 constitutes a part of the air passageportion of the fan shroud 30. The motor case 31D has an air inletopening 32D for introducing the air outside of the cooling unit into themotor case 31D, and first and second air outlet openings 33D, 34D fordischarging the air from the motor case 31D.

The air inlet opening 32D is provided on an upper portion of a secondside wall of the motor case 31D, the second side wall being opposite tothe driving shaft 17. The air inlet opening 32D is open to the directionopposite to the direction X. The first air outlet opening 33D isprovided in the first side wall, which forms the downstream portion ofthe motor case 31D. The first air outlet opening 33D is provided toallow communication between the inside of the motor case 31D and thenegative pressure region of the core-cooling fan 10, that is, the frontarea of the core-cooling fan 10. In other words, the first air outlet33D is provided to open to the inside of the fan shroud 30,particularly, to the air passage portion of the fan shroud 30. Thesecond air outlet opening 34D is located at a rear portion of the motorcase 31D. The second air outlet opening 34D is located more to a rearposition than the driving shaft 17.

According to the above-described positions of the air inlet opening 32Dand the first and second air outlet openings 33D, 34D, the air outsideof the motor case 31D is suctioned to the inside of the motor case 31Dfrom the air inlet opening 32D when the motor-cooling fan 20A isoperated. Inside of the motor case 31D, the suctioned air flows in therearward direction. While flowing along the fins 41, which extend in thedirection X, the suctioned air cools the control device 40. Then, theair collides with the rear wall of the motor case 31D and thus flowsdownwardly. The air flows around the motor 19 and further flows towardthe downstream location of the motor-cooling fan 20A. Then, the airflows out from the motor case 31D through the first and second airoutlet openings 33D, 34D. The air flowing out from the first air outletopening 33D is blown out to the negative pressure region of thecore-cooling fan 10. The air flowing out from the second air outletopening 34D is blown out to the downstream location of the core-coolingfan 10.

The motor case 31D can be made of a resin material, such aspolypropylene, containing glass fiber, talc, and the like so as to havesufficient strength. The motor case 31D can be integrally formed withthe fan shroud 30. Alternatively, the motor case 31D can be formedseparately from the fan shroud 30. In such a case, the motor case 31D isfixed to the fan shroud 30, another member mounted in the vehicle, or apar of the vehicle body.

In the present embodiment, the air inlet opening 32D is formed at a partof the second side wall of the motor case 31D and is smaller than theair inlet opening 32A, 32B, 32C of the second embodiment. Inside of themotor case 31D, the separation wall 35 is provided to separate a firstspace 36 where the control device 40 is arranged from a second space 37where the motor 19 is arranged.

The air suctioned from the air inlet opening 32D first flows in thefirst space 36. In the first space 36, the air flows around the controldevice 40. Then, the air enters the second space 37 and flows around themotor 19. Thereafter, the air flows out from the motor case 31D from thefirst and second air outlet openings 33D, 34D. For example, theseparation wall 35 forms an opening for allowing communication betweenthe first space 36 and the second space 37 with the rear wall of themotor case 31D, as shown in FIG. 8.

Since the air inlet opening 32D is formed at a part of the second sidewall of the motor case 31D, the velocity of air supplied to the controldevice 40 is increased. As such, the cooling effect further improves. Inaddition, the control device 40 is located upstream of the motor 19 withrespect to the flow of air. Therefore, the control device 40 can becooled prior to the motor 19.

Fifth Embodiment

A fifth embodiment of the present invention will now be described withreference to FIG. 10. In the present embodiment, the rotation shaft 18of the motor-cooling fan 20A is coupled to a rotation shaft 17 a of themotor device through a joint 50.

The cooling unit of the present embodiment is similar to the coolingunit of the second embodiment, except that the motor device has a firstshaft part 17 a and a second shaft part 17 b, in place of the drivingshaft 17, and the first shaft part 17 a is coupled to the rotation shaft18 of the motor-cooling fan 20A through the joint 50. The effectssimilar to the second embodiment are achieved by the similar structures.

Here, the first shaft part 17 a is directly connected to the motor 19.The joint 50 is not limited to one embodiment, but can have any jointstructure capable of coaxially connecting the first shaft part 17 a andthe rotation shaft 18. For example, the joint 50 can be constructed of amotor-side gear fixed to the first shaft part 17 a and a fan-side gearfixed to the rotation shaft 18 of the motor-cooling fan 20A. Themotor-side gear and the fan-side gear are engaged with each other,thereby to connect the first shaft part 17 a to the rotation shaft 18.

In the present embodiment, the first driving gear 15 and the seconddriving gear 16 are fixed to the second shaft part 17 b. The secondshaft part 17 b extends parallel to the core 2, similar to the drivingshaft 17. The shaft 17 b, the rotation shaft 18 of the motor-cooling fan20A, and the first shaft part 17 a are coaxially aligned.

Sixth Embodiment

A sixth embodiment of the present invention will now be described withreference to FIGS. 11 to 15. In the sixth embodiment, the cooling unithas a motor-cooling fan 20C into which a joint 60 is integrated, inplace of the joint 50 of the fifth embodiment. Other structures of thecooling unit are similar to the above embodiments.

As shown in FIG. 11, the motor-cooling fan 20C has a boss part 22C andblades 21C radially extending from the boss part 22C. The boss part 22Cincludes an external gear member 61 and an internal gear member 65. Theexternal gear member 61 is disposed closer to the first shaft part 17 athan the internal gear member 65, and is formed with the rotation shaft18 at its center. The internal gear member 65 is disposed on an outerside of the external gear member 61 and is engaged with the externalgear member 61. That is, the boss part 22C is constructed of theexternal gear member 61 and the internal gear member 65.

As shown in FIGS. 12 and 13, the external gear member 61 includes a discportion 62 and external teeth 63 projecting from an outer circumferenceof the disc portion 62 in a radial outward direction. The external teeth63 are arranged at equal intervals along the circumference of the discportion 62. For example, the external gear member 61 has eight externalteeth 63. The disc portion 62 is integrally connected to the first shaftpart 17 a at its center.

As shown in FIGS. 14 and 15, the internal gear member 65 includes acylindrical portion 68 and internal teeth 67. The cylindrical portion 68has an end wall, and an end of the shaft 17 b carrying the first andsecond driving gears 15, 16 is integrally connected to a center of theend wall. The internal teeth 67 project from an inner surface of thecylindrical portion 68 in a radially inward direction. The internalteeth 67 are arranged at equal intervals in a circumferential direction.For example, the internal gear member 65 has eight internal teeth 67.The blades 21C extends from an outer surface of the cylindrical portion68.

The internal teeth 67 of the internal gear member 65 are arranged tocorrespond to grooves between the external teeth 63 of the disc portion62 of the external gear member 61. The internal teeth 67 are capable ofcontacting the outer surface of the disc portion 62 between the externalteeth 63. The external teeth 63 of the external gear member 61 arearranged to correspond to grooves between the internal teeth 67 of thecylindrical portion 68. The external teeth 63 are capable of contactingthe inner surface of the cylindrical portion 68 between the internalteeth 67.

In the present embodiment, the joint 60 is integrated into themotor-cooling fan 20C, particularly, into the boss part 22C. Themotor-cooling fan 20C having the joint 60 is formed of a resin materialsuch as by injection molding using a predetermined die. The joint 60 is,for example, made of polypropylene, nylon or the like, containing glassfiber, talc and the like so as to have sufficient strength.

The structure of the shaft and the joint 60 of the present embodimentcan be employed in the cooling units of the above-described embodiments.

In the present embodiment, the cooling unit has the joint 60 coaxiallyconnecting the second shaft part 17 b, which is connected to therotation shafts 13 of the core-cooling fans 10 through the gears 14, 15,16, and the first shaft part17 a directly connected to the motor 19. Thejoint 60 is integrally formed into the motor-cooling fan 20C.

In such a construction, the size of the cooling unit in the longitudinaldirection of the shafts 17 a, 17 b, 18 can be reduced, and axialdisplacements of the shafts 17 a, 17 b, 18 are reduced. Further, theentire size of the cooling unit is reduced. In addition, the number ofcomponent parts and the number of assembling steps are reduced. Sincethe joint 60 is integrally formed with the boss part 22C of themotor-cooling fan 20C, arrangement spaces and manufacturing costs arereduced.

Other Embodiments

The various exemplary embodiments of the present invention are describedhereinabove. However, the present invention is not limited to the abovedescribed exemplary embodiments, but may be implemented in various otherways without departing from the spirit of the invention. Further, thepresent invention can be implemented by partly combining the aboveexemplary embodiments in various ways.

In the above embodiments, the fan shroud 30 is made of resin.Alternatively, the fan shroud 30 can be made of a metal. In such a case,the fan shroud 30 can be made by pressing using a die, welding, and thelike.

In the above embodiments, the motor-cooling fans 20, 20A, 20B, 20C aredisposed downstream of the motor 19 with respect to the flow of air.Alternatively, the motor-cooling fans 20, 20A, 20B, 20C can be disposedupstream of the motor 19.

The number of the core-cooling fans 10 is not limited to two. The fanshroud 30 can be configured to support one core-cooling fan 10 or threeor more core-cooling fans 10.

In the above embodiments, each of the core-cooling fans (blowers) 10includes the single fan with respect to the front and rear direction.However, the core-cooling fan 10 can be constructed of a contra-rotatingblower in which two fans are aligned in the front and rear direction androtated in contra-directions. The contra-rotating blower has high fanefficiency. The rotation shafts of the fans are aligned in the front andrear direction and coupled to the driving shaft 17 through gears.

The fan shroud 30 and the radiator 1 can be fixed in various ways, suchas by screws, clips, brackets, and the like.

Additional advantages and modifications will readily occur to thoseskilled in the art. The invention in its broader term is therefore notlimited to the specific details, representative apparatus, andillustrative examples shown and described.

1. A cooling unit for generating air for cooling a core of a heatexchanger, comprising: a motor; a driving shaft extending from themotor, the driving shaft to be disposed parallel to the core; a firstfan to be opposed to the core for generating the air for cooling thecore, the first fan having a first rotation shaft connected to thedriving shaft through a gear to be rotated by the driving shaft; a fanshroud supporting the first fan and configured to conduct the air fromthe core toward the first fan; and a second fan having a second rotationshaft and configured to generate air for cooling the motor, wherein thesecond rotation shaft is disposed coaxial with the driving shaft androtatable with the driving shaft such that the second fan is rotated bythe driving shaft when the first fan is rotated.
 2. The cooling unitaccording to claim 1, wherein the driving shaft includes a first shaftpart and a second shaft part, the first shaft part is directly connectedto the motor, and the second shaft part is connected to the firstrotation shaft of the first fan through the gear, the cooling unitfurther comprising: a joint coaxially coupling the first shaft part andthe second shaft part.
 3. The cooling unit according to claim 2, whereinthe second fan has a boss part forming the second rotation shaft andblades extending from the boss part, and the joint is integrally formedinto the boss part.
 4. The cooling unit according to claim 1, furthercomprising: a case housing the motor therein, wherein the case has anair inlet opening through which air is drawn to an inside of the case byrotation of the second fan and an air outlet opening through which airis discharged from the inside of the case, and the air outlet opening isprovided downstream of the second fan with respect to a flow of airgenerated by the second fan and upstream of the first fan with respectto a flow of air generated by the first fan, the air outlet openingallowing communication between the inside of the case and a negativepressure region of the first fan.
 5. The cooling unit according to claim4, wherein the air outlet opening is a first air outlet opening, and thecase has a second air outlet opening provided downstream of the secondfan with respect to the flow of air generated by the second fan anddownstream of the first fan, the second air outlet opening allowingcommunication between the inside of the case and a downstream locationof the first fan.
 6. The cooling unit according to claim 1, wherein thesecond fan includes a centrifugal fan.
 7. The cooling unit according toclaim 1, further comprising: a case housing the motor therein, whereinthe motor is connected to an end of the driving shaft and is locatedimmediately downstream of the heat exchanger, and the case has an airinlet opening on an axial end thereof opposite to the driving shaft fordrawing air into the case.
 8. The cooling unit according to claim 7,wherein the air inlet opening is formed on an entirety of the axial endof the case.
 9. The cooling unit according to claim 1, furthercomprising: a control device adapted to control an operation of thesecond fan; and a case housing the control device, the motor and thesecond fan therein, wherein the case has a separation wall separating afirst space where the control device is disposed from a second spacewhere the motor is disposed, the case further has an air inlet openingthrough which air is suctioned in the case by rotation of the secondfan, and the first space is located upstream of the second space withrespect to a flow of the air suctioned from the air inlet opening. 10.The cooling unit according to claim 1, wherein the first fan is one of aplurality of first fans aligned in a direction parallel to the core, thedriving shaft is disposed parallel to the core downstream of the firstfans with respect to a flow of the air generated by the first fans. 11.The cooling unit according to claim 1, further comprising: a casehousing the motor and the second fan therein, wherein the case isintegrally formed with the fan shroud.